Regarding arithmetic games, I much prefer https://www.chiark.greenend.org.uk/~sgtatham/puzzles/js/keen.html https://www.chiark.greenend.org.uk/~sgtatham/puzzles

Regarding arithmetic games, I much prefer https://www.chiark.greenend.org.uk/~sgtatham/puzzles/js/keen.html https://www.chiark.greenend.org.uk/~sgtatham/puzzles/js/keen... At least half of that preference is the ability to use keyboard controls. The math is also more tailorable to user ability (use the "type" menu), though within each game it goes from hard to easy.